Ink jet printers comprise two basic types, namely, printers having movable printheads which traverse the print media and deposit ink droplets in a defined pattern on each swath of the printer cartridge and printers having substantially fixed page wide printheads which contain an array of nozzles along the length of the printhead.
In a moveable printhead design, one or more printer cartridges each containing a printhead are attached to a movable carriage which traverses the print media as the media moves transverse to the carriage movement through the printer. Use of multiple printer cartridges rather than a single cartridge attached to a movable carriage greatly increases print speed. However, in order to obtain the highest quality printing, alignment between the print cartridges is critical and is often difficult to maintain over the life of the printer. As the print cartridges are changed, slight misalignment of the cartridges occurs thereby degrading the print quality. The alignment problems associated with multiple printer cartridges are not present when using a single print cartridge, however, a single cartridge printer cannot print at the higher speeds obtainable by use of multiple printer cartridges.
In an effort to increase printer speed without sacrificing print quality, page wide printhead arrays having a length equal to, or slightly less, than the width of print media have been developed. The page wide printhead arrays are set at about 90 degrees or substantially perpendicular to the direction of travel of print media through the printer. Such large or page wide printhead arrays greatly increase the printing speeds but require a higher density of nozzles on the printhead in order to obtain the same print quality obtained by the use of a movable printhead. Moveable printheads do not suffer from lower print quality for printheads having the same nozzle density as the page wide printheads because such printheads can be moved across the print media to create a higher density of ink droplets on the media.
One disadvantage of a page wide printhead array is the difficulty associated with manufacturing such a printhead with a sufficiently high density of nozzles sufficient to produce the desired print quality. Providing a high density of nozzles on the printhead is complicated by the routing requirements for the electrical tracing to the ink ejection devices and for the ink channels and flow features on the printheads for flow of ink to the nozzle chambers adjacent each nozzle.
Another disadvantage of page wide printheads oriented perpendicular to the direction of travel of the print media is that such printheads consume excessive amounts of power because all or a significantly large percentage of the nozzles of the printhead must operate simultaneously to provide full ink coverage on the print media, such as for a fully printed page.
An object of the invention is therefore to provide an improved high speed, high quality printer.
Another object of the invention is to provide a printer having an improved page wide printhead array.
A further object of the invention is to provide a printer which improves print quality without sacrificing print speed.
Still another object of the invention is to reduce the power consumption of a page wide printhead device.
Another object of the invention is to reduce the manufacturing costs and difficulties associated with producing page wide printhead arrays.